The use of water-dispersible linear sulfopolyesters in hair spray formulations has been disclosed in U.S. Pat. Nos. 4,300,580 and 5,158,762. U.S. Pat. No. 4,300,580, issued Nov. 17, 1981, and assigned to Eastman Kodak Company, discloses hair grooming formulations containing a sulfopolyester comprising a dicarboxylic acid, a diol wherein at least 20 mole percent is a poly(ethylene glycol), and 8 to 45 mole percent of a dicarboxylic acid sulfomonomer. U.S. Pat. No. 5,158,762, issued Oct. 27, 1992, and assigned to ISP Investments Inc., discloses hair spray compositions containing a blend of two polymers. One of the polymers is a sulfopolyeser comprising a dicarboxylic acid, a diol wherein at least 40 mole percent is 1,4-cyclohexanedimethanol, and 16 to 25 mole percent of a sulfomonomer. U.S. Pat. No. 5,158,762 states that useful sulfopolyesters are AQ 38 and AQ 55 which are available from Eastman Chemical Company. It is interesting to note that while the patent discloses a range of sulfomonomer of 16 to 25 mole percent, AQ 38 has 11 mole percent sulfomonomer. Moreover, AQ 38 has 22 mole percent of 1,4-cyclohexanedimethanol which is below the 40 mole percent requirement set forth in U.S. Pat. No. 5,158,762. In contrast, neither AQ 38 nor AQ 55 are operable in the present invention. The other polymer in U.S. Pat. No. 5,158,762 is a water soluble polymer which includes polyvinyl pyrrolidone (PVP) and polyvinyl acetate.
Such hair grooming compositions generally perform effectively in providing most of the properties considered desirable for hair preparation, including fine spray patterns, prolonged curl retention under humid conditions, good holding power and resistance to build-up. However, these and other hair spray formulations available in the art are generally cloudy and contain precipitate that clogs the exit ports of aerosol cans or pump containers.
The present inventors have unexpectedly discovered four critical ranges that are necessary to produce clear hair spray compositions. The diol component of the sulfopolyester must contain 10 to 30 mole percent 1,4-cyclohexanedimethanol; the sulfopolyester must contain 18.5 to 22.5 mole percent sulfomonomer; the sulfopolyester must have a glass transition temperature (Tg) of 40.degree. C. to 60.degree. C.; and the sulfopolyester must have an inherent viscosity (I.V.) of 0.2 to 0.6 dl/g. The clear hair spray compositions of the present invention exhibit less than 30 NTU's which is a measure of turbidity. In the cosmetic field greater than 30 NTU's is characteristic of a cloudy mixture that is visible to the eye.